Android NDK链接V8静态库:找不到符号，但它们在那里 [英] Android NDK linking V8 static library: cannot find symbols, but they are there
问题描述
我一直把头发拉到这个上面.我正在 Ubuntu 12.04 64 位上开发.我创建了一个嵌入了 V8 的原生 Android 应用程序，但重新启动计算机后，它不再与 V8 链接！我尝试重新安装 ndk 并重新编译 V8，但无济于事.看起来链接器确实包含静态库，但没有在其中找到符号.我用nm检查，符号似乎在那里.
I've been pulling my hair out over this one. I am developing on Ubuntu 12.04 64-bit. I created a native Android app with V8 embedded in it, but after rebooting my computer, it doesn't link with V8 anymore! I've tried reinstalling ndk and recompiling V8, but to no avail. It appears the linker does include the static libraries, but doesn't find the symbols in them. I checked with nm, and the symbols appear to be there.
当我运行 ndk_build 时，我得到以下输出:
When I run ndk_build, I get the following output:
$ ndk-build V=1
rm -f ./libs/armeabi/lib*.so ./libs/armeabi-v7a/lib*.so ./libs/armeabi-v7a-hard/lib*.so ./libs/mips/lib*.so ./libs/x86/lib*.so
rm -f ./libs/armeabi/gdbserver ./libs/armeabi-v7a/gdbserver ./libs/armeabi-v7a-hard/gdbserver ./libs/mips/gdbserver ./libs/x86/gdbserver
rm -f ./libs/armeabi/gdb.setup ./libs/armeabi-v7a/gdb.setup ./libs/armeabi-v7a-hard/gdb.setup ./libs/mips/gdb.setup ./libs/x86/gdb.setup
[armeabi] Compile++ thumb: native-activity <= main.cpp
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/arm-linux-androideabi-g++ -MMD -MP -MF ./obj/local/armeabi/objs/native-activity/main.o.d -fpic -ffunction-sections -funwind-tables -fstack-protector -no-canonical-prefixes -march=armv5te -mtune=xscale -msoft-float -fno-exceptions -fno-rtti -mthumb -Os -g -DNDEBUG -fomit-frame-pointer -fno-strict-aliasing -finline-limit=64 -Ijni/include -I/home/schooten/bin/packages/android-ndk-r9d/sources/android/native_app_glue -I/home/schooten/bin/packages/android-ndk-r9d/sources/cxx-stl/system/include -Ijni -DANDROID -Wa,--noexecstack -Wformat -Werror=format-security -I/home/schooten/bin/packages/android-ndk-r9d/platforms/android-9/arch-arm/usr/include -c jni/main.cpp -o ./obj/local/armeabi/objs/native-activity/main.o
[armeabi] Compile thumb : android_native_app_glue <= android_native_app_glue.c
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/arm-linux-androideabi-gcc -MMD -MP -MF ./obj/local/armeabi/objs/android_native_app_glue/android_native_app_glue.o.d -fpic -ffunction-sections -funwind-tables -fstack-protector -no-canonical-prefixes -march=armv5te -mtune=xscale -msoft-float -mthumb -Os -g -DNDEBUG -fomit-frame-pointer -fno-strict-aliasing -finline-limit=64 -I/home/schooten/bin/packages/android-ndk-r9d/sources/android/native_app_glue -DANDROID -Wa,--noexecstack -Wformat -Werror=format-security -I/home/schooten/bin/packages/android-ndk-r9d/platforms/android-9/arch-arm/usr/include -c /home/schooten/bin/packages/android-ndk-r9d/sources/android/native_app_glue/android_native_app_glue.c -o ./obj/local/armeabi/objs/android_native_app_glue/android_native_app_glue.o
[armeabi] StaticLibrary : libandroid_native_app_glue.a
rm -f obj/local/armeabi/libandroid_native_app_glue.a
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/arm-linux-androideabi-ar crsD ./obj/local/armeabi/libandroid_native_app_glue.a ./obj/local/armeabi/objs/android_native_app_glue/android_native_app_glue.o
[armeabi] StaticLibrary : libstdc++.a
rm -f obj/local/armeabi/libstdc++.a
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/arm-linux-androideabi-ar crsD ./obj/local/armeabi/libstdc++.a
[armeabi] SharedLibrary : libnative-activity.so
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/arm-linux-androideabi-g++ -Wl,-soname,libnative-activity.so -shared --sysroot=/home/schooten/bin/packages/android-ndk-r9d/platforms/android-9/arch-arm ./obj/local/armeabi/objs/native-activity/main.o ./obj/local/armeabi/libandroid_native_app_glue.a jni/lib/libv8_libbase.arm.a jni/lib/libv8_nosnapshot.a jni/lib/libv8_base.a jni/lib/libstlport_static.a ./obj/local/armeabi/libstdc++.a -lgcc -no-canonical-prefixes -Wl,--no-undefined -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now -L/home/schooten/bin/packages/android-ndk-r9d/platforms/android-9/arch-arm/usr/lib -llog -landroid -lEGL -lGLESv1_CM -llog -lstdc++ -lc -lm -o ./obj/local/armeabi/libnative-activity.so
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/objs/native-activity/main.o: in function __clearColor(v8::FunctionCallbackInfo<v8::Value> const&):jni/main.cpp:88: error: undefined reference to 'v8::Value::Int32Value() const'
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/objs/native-activity/main.o: in function __clearColor(v8::FunctionCallbackInfo<v8::Value> const&):jni/main.cpp:89: error: undefined reference to 'v8::Value::Int32Value() const'
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/objs/native-activity/main.o: in function __clearColor(v8::FunctionCallbackInfo<v8::Value> const&):jni/main.cpp:90: error: undefined reference to 'v8::Value::Int32Value() const'
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/objs/native-activity/main.o: in function __clearColor(v8::FunctionCallbackInfo<v8::Value> const&):jni/main.cpp:91: error: undefined reference to 'v8::Value::Int32Value() const'
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/objs/native-activity/main.o: in function run_javascript(char*):jni/main.cpp:101: error: undefined reference to 'v8::Isolate::New()'
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/objs/native-activity/main.o: in function run_javascript(char*):jni/include/v8.h:4045: error: undefined reference to 'v8::Isolate::Enter()'
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/objs/native-activity/main.o: in function run_javascript(char*):jni/main.cpp:104: error: undefined reference to 'v8::HandleScope::HandleScope(v8::Isolate*)'
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/objs/native-activity/main.o: in function run_javascript(char*):jni/main.cpp:108: error: undefined reference to 'v8::ObjectTemplate::New(v8::Isolate*)'
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/objs/native-activity/main.o: in function run_javascript(char*):jni/main.cpp:110: error: undefined reference to 'v8::ObjectTemplate::New(v8::Isolate*)'
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld: ./obj/local/armeabi/objs/native-activity/main.o: in function run_javascript(char*):jni/main.cpp:112: error: undefined reference to 'v8::String::NewFromUtf8(v8::Isolate*, char const*, v8::String::NewStringType, int)'
... etc ...
特别是，这一行告诉我包含 *.a 文件:
In particular, this line tells me that the *.a files are included:
/home/schooten/bin/packages/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/arm-linux-androideabi-g++ -Wl,-soname,libnative-activity.so -shared --sysroot=/home/schooten/bin/packages/android-ndk-r9d/platforms/android-9/arch-arm ./obj/local/armeabi/objs/native-activity/main.o ./obj/local/armeabi/libandroid_native_app_glue.a jni/lib/libv8_libbase.arm.a jni/lib/libv8_nosnapshot.a jni/lib/libv8_base.a jni/lib/libstlport_static.a ./obj/local/armeabi/libstdc++.a -lgcc -no-canonical-prefixes -Wl,--no-undefined -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now -L/home/schooten/bin/packages/android-ndk-r9d/platforms/android-9/arch-arm/usr/lib -llog -landroid -lEGL -lGLESv1_CM -llog -lstdc++ -lc -lm -o ./obj/local/armeabi/libnative-activity.so
我的 Android.mk 如下所示:
My Android.mk looks like this:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := stlport
LOCAL_MODULE_FILENAME := stlport_static
LOCAL_SRC_FILES := lib/libstlport_static.a
include $(PREBUILT_STATIC_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := v8_base
LOCAL_MODULE_FILENAME := v8_base_static
LOCAL_SRC_FILES := lib/libv8_base.a
include $(PREBUILT_STATIC_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := v8_nosnapshot
LOCAL_MODULE_FILENAME := v8_nosnapshot_static
LOCAL_SRC_FILES := lib/libv8_nosnapshot.a
include $(PREBUILT_STATIC_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := v8_libbase
LOCAL_MODULE_FILENAME := v8_libbase_static
LOCAL_SRC_FILES := lib/libv8_libbase.arm.a
include $(PREBUILT_STATIC_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := native-activity
LOCAL_SRC_FILES := main.cpp
LOCAL_LDLIBS := -llog -landroid -lEGL -lGLESv1_CM
LOCAL_STATIC_LIBRARIES := android_native_app_glue v8_libbase v8_nosnapshot v8_base stlport
LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
include $(BUILD_SHARED_LIBRARY)
$(call import-module,android/native_app_glue)
LOCAL_STATIC_LIBRARIES 顺序是根据经验确定的.我又摆弄了一些，但无济于事.我什至尝试了 LOCAL_WHOLE_STATIC_LIBRARIES.我用 nm 检查了符号的存在:
The LOCAL_STATIC_LIBRARIES order was determined empirically. I fiddled with it some more, but to no avail. I even tried LOCAL_WHOLE_STATIC_LIBRARIES. I checked the existence of symbols with nm:
arm-linux-gnueabi-nm jni/lib/libv8_base.a | grep Int32Value
U _ZNK2v85Value10Int32ValueEv
00000000 T _ZNK2v85Value10Int32ValueEv
U _ZNK2v85Value10Int32ValueEv
arm-linux-gnueabi-nm jni/lib/libv8_base.a | grep Utf8Value
00000000 T _ZN2v86String9Utf8ValueC1ENS_6HandleINS_5ValueEEE
00000000 T _ZN2v86String9Utf8ValueC2ENS_6HandleINS_5ValueEEE
00000000 T _ZN2v86String9Utf8ValueD1Ev
00000000 T _ZN2v86String9Utf8ValueD2Ev
U _ZN2v86String9Utf8ValueC1ENS_6HandleINS_5ValueEEE
U _ZN2v86String9Utf8ValueD1Ev
U _ZN2v86String9Utf8ValueC1ENS_6HandleINS_5ValueEEE
U _ZN2v86String9Utf8ValueD1Ev
U _ZN2v86String9Utf8ValueC1ENS_6HandleINS_5ValueEEE
U _ZN2v86String9Utf8ValueD1Ev
U _ZN2v86String9Utf8ValueC1ENS_6HandleINS_5ValueEEE
U _ZN2v86String9Utf8ValueD1Ev
U _ZN2v86String9Utf8ValueC1ENS_6HandleINS_5ValueEEE
U _ZN2v86String9Utf8ValueD1Ev
我不是名字修改专家，但他们似乎在那里.这些值都是零，但我认为这是正常的.
I am no expert at name munging, but it appears they are there. The values are all zeroes, but I believe this is normal.
所以我想，也许链接器不理解静态库，它默默地失败了.
但是如何检查链接器为什么无法拾取符号?
So I figured, maybe the linker doesn't understand the static library, and it fails silently.
But how do I check why the linker is failing to pick up the symbols?
推荐答案
在朋友的帮助下，我终于修好了.首先，我尝试了一种解决方法，尝试将 V8 链接为共享库，但结果并不好，因为 我使用的 NDK 原生活动接口与加载其他共享对象不兼容.
I finally fixed it, with help of a friend. First I tried a workaround where I tried to link V8 as a shared library, which didn't turn out well because the NDK native activity interface I'm using turned out to be incompatible with loading additional shared objects.
我的静态库存在两个不同的问题.第一个也是最重要的一点是V8构建的静态库不适合链接.您可以使用以下方法进行检查:
There were two different issues going on with my static libraries. The first and most important one is that the static libraries built by V8 are not suitable for linking. You can check this by using:
ar x [static_library.a]
这通常会从库中提取 *.o 对象.在这种情况下，它报告:
which will normally extract the *.o objects from the library. In this case, it reported:
`x' cannot be used on thin archives
精简存档只是一组对 *.o 文件的绝对路径的引用，没有实际内容.这就解释了为什么我的构建在我从 V8 构建树中移动或删除原始 *.o 文件时停止工作.奇怪的是，链接器对此保持沉默.
A thin archive is just a set of references to the absolute paths of the *.o files, and no actual content. That explains why my build stopped working at one point where I moved or deleted the original *.o files from the V8 build tree. Strangely, the linker kept silent about that.
创建静态库目前不是 V8 中的构建选项.值得庆幸的是，这家伙有一个补丁来创建正确的V8 中的静态库.
Creating static libraries is not currently a build option in V8. Thankfully, this guy has a patch for creating proper static libraries in V8.
在我这样做之后，应用程序仍然没有链接，因为我第一次复制了错误的文件.事实证明，静态库也是为主机架构构建的(不要问我为什么)，我不小心复制了这些.我了解到您可以使用:
The app still didn't link after I did that, because I copied the wrong files the first time round. As it turned out, the static libraries are also built for the host architecture (don't ask me why), and I accidentally copied those. I learned that you can use:
file objectfile.o
看看它是什么架构.因此我发现我的静态库是 i386 而不是 arm.因此，链接器跳过了这些文件，因为架构不匹配(您可以在静态库中混合架构).
to see what architecture it is. Hence I found my static libraries were i386 and not arm. So, the linker was skipping these files, because the architecture didn't match (you can mix architectures in a static library).
这是我根据 Curu Wong 的补丁为 V8 3.27.28 制作的 V8 补丁.我将尝试提交此补丁.补丁 1:
Here is the V8 patch that I made to V8 3.27.28 based on the patch by Curu Wong. I will try to get this patch committed. Patch 1:
~/Work/javascript/Engines/v8-trunk/tools/gyp$ diff -u v8.gyp.orig v8.gyp
--- v8.gyp.orig 2014-06-18 21:09:59.368336736 +0200
+++ v8.gyp 2014-06-18 21:12:20.264331660 +0200
@@ -108,6 +108,7 @@
{
'target_name': 'v8_snapshot',
'type': 'static_library',
+ 'standalone_static_library': 1,
'conditions': [
['want_separate_host_toolset==1', {
'toolsets': ['host', 'target'],
@@ -180,6 +181,7 @@
{
'target_name': 'v8_nosnapshot',
'type': 'static_library',
+ 'standalone_static_library': 1,
'dependencies': [
'v8_base',
],
@@ -237,6 +239,7 @@
{
'target_name': 'v8_base',
'type': 'static_library',
+ 'standalone_static_library': 1,
'dependencies': [
'v8_libbase.<(v8_target_arch)',
],
补丁 2:
~/Work/javascript/Engines/v8-trunk/third_party/icu$ diff -u icu.gyp.orig icu.gyp
--- icu.gyp.orig 2014-06-18 21:10:22.060335920 +0200
+++ icu.gyp 2014-06-18 21:15:06.468325674 +0200
@@ -56,6 +56,7 @@
{
'target_name': 'icudata',
'type': 'static_library',
+ 'standalone_static_library': 1,
'defines': [
'U_HIDE_DATA_SYMBOL',
],
@@ -141,6 +142,11 @@
{
'target_name': 'icui18n',
'type': '<(component)',
+ 'conditions': [
+ [ 'component!="shared_library"', {
+ 'standalone_static_library': 1,
+ }],
+ ],
'sources': [
'<@(icui18n_sources)',
],
@@ -241,6 +247,11 @@
{
'target_name': 'icuuc',
'type': '<(component)',
+ 'conditions': [
+ [ 'component!="shared_library"', {
+ 'standalone_static_library': 1,
+ }],
+ ],
'sources': [
'<@(icuuc_sources)',
],
这篇关于Android NDK链接V8静态库:找不到符号，但它们在那里的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
